The naval operational environment is constantly in flux, and small advantages can be the strategic difference during an engagement. In recent years almost all nations in possession of submarines have put forth significant resources to make submarines and torpedoes operate more quietly.
To address these evolving threats, the Royal Canadian Navy (RCN) is taking steps to improve the detection abilities of its Halifax-class frigates. “A lot of the resources that were put forward at the end of the Cold War were for passive sonars,” said Lieutenant-Commander (LCdr) Félix Rancourt.“The way passive sonar works is it listens to the sound in the ocean and tries to find the noise that the submarine makes in the water.”
When the Halifax-class frigates were built, it was to operate in the Northern Atlantic and find Soviet nuclear submarines. Passive sonar technology is designed for long range detection of “noisy” targets in large bodies of water. “The submarines that are built today are made to operate close to the littoral, close to the coast in heavy traffic environments,” said LCdr Rancourt. “Though this is not necessarily a change in platform. It is a change in where the platform operates and where the Canadian Navy subsequently operates.”
Torpedoes are improving too. In the early days torpedoes found their targets using fairly rudimentary techniques. Now they are getting more and more sophisticated, including advancements in their propulsion systems which make them harder to detect.
“In the past we would focus on trying to listen for the torpedo's engine from a passive point of view,” said LCdr Rancourt.
“But now because they are quieter, we're looking at other options of what we can detect to be able to know where the torpedoes are.”
These advancements allow torpedoes to get closer to their target before they can be detected, which poses a greater risk to all surface ships.
“Why this is so important is that heavy-weight torpedoes are lethal to surface ships as compared to attacks with missiles,” said Ken Johansen from Underwater Warfare Suite Upgrade Engineering.
It only takes one heavy-weight torpedo to severely cripple or even sink a ship. So it is very important that surface ships keep awareness of what’s around them below the water.
Some of the improvements to counter the new capabilities of enemy submarines and torpedoes include the installation of a new Towed Array Sonar with Inline Projector Technology, Wideband Hull Mounted Sonars (WHMS) and inclusion of the Torpedo Sonar Intercept & Classification (TORSIC) system, a technology common on submarines that detects sonar being produced by an enemy torpedo.
Defence Research and Development Canada (DRDC), the Department of National Defence’s research agency, laid much of the foundation for the new sensor array being installed on the Halifax-class during the Towed Integrated Active Passive Sonar project conducted in the late 90’s. As part of DRDC’s research, they looked into the feasibility of including a horizontal active source in tow with the receiver which is the concept for the product the RCN is implementing.
“You have your tow, and then you have an active portion and then a passive portion at the end of it. That kind of technology, DRDC was significantly involved in for that project,” recalled LCdr Rancourt.
The Canadian developed active and passive towed array and hull mounted sonars offer unique capabilities and world leading performance. Both new sensors leverage decades of Canadian anti-submarine warfare industrial expertise supported by RCN and DND investment.
“UWSU profoundly changes the ship’s operational capabilities – including detection,” said General Dynamics Mission Systems–Canada’s UWSU Program Manager, Mark Thibodeau.
“The Halifax-class frigates will be able to detect quieter targets at increased ranges providing the greatest possible detection capability to protect ships from underwater threats. It’s a real game-changer.”
The integrated capabilities will facilitate collaborative anti-submarine warfare operations with other ships or airborne assets, including Canada’s CP-140 Aurora and CH-148 Cyclone fleets.
So, what does this all mean?
The improved sensors and sonars working in concert provide a much more detailed account of the new environment a ship and its crew operates in. These new environments are considered shallow in relation to historical environments. For example, the Persian Gulf has an average depth of approximately 50 metres whereas the Atlantic Ocean has an average depth of over 3,000 metres. The upgraded sensors and sonars are better suited to identify different types of contacts, which is important in heavily trafficked areas.
Having a better detection capability increases the window operators and command teams have for decision making, and increased decision making time makes sailors safer.
These new sensors and sonars will also lay the foundation for the future. Since the 70s and 80s significant advancements were made in a ship’s ability to detect threats by introducing better software and greater processing speeds and power while keeping the old sensors and closed systems.
With the new sensors, and plans to build new onboard management systems using an open architecture allowing improvements to be made more expediently, the RCN’s ability to adapt to its environment will be greater than ever.
“It’s really a success story. If you think about the way Canada should be developing capabilities, to me that is the way it should be,” said LCdr Rancourt.